Quick one step boxcar name and number change

I was asked to change the numbers and names of some boxcars. They're not at the repair facility; and the manager wasn't keen on having me paint over the existing numbers one day, then put new letters on another day. It might have been so that there wasn't any confusion between what was painted and the electronic ID that the cars have.
At any rate, I had to come up with a way to do it in one step. This car had a name change before; that's when the lighter blue area and the NCYR 601 were put on. Vinyl letters had already been cut for the current name change, so I used those. Normally I use paint for lettering boxcars, because they sometimes get graffiti on them; and I would want repair layers to be all paint, rather than alternating between paint and vinyl. Most vinyl isn't paint receptive, I wouldn't want layers falling off somewhere far away. On the other hand, I knew a guy that worked at a theme park, he regularly put paint blends over vinyl, and didn't have problems, as far as I know.
Anyway, the pictures below show the process:
Here I've wiped the area down with a cleaning cloth, and knocked off any surface irregularities with a scraper. That way the little bumps won't make big bubbles under the vinyl. Then I put the new vinyl letters over the existing painted letters. I'll do the section with KX 608 completely, then the section with HR second, this will make less ladder moving.

Now a stop at the mobile paint mixing bench, to try and come up with a similar blue to the one on the car. When getting paint for the job, I hastily grabbed what I thought would be the right blue from the shelf. It turned out to be quite a ways off, but I had also brought a small amount of process blue lettering enamel. I poured some of the wrong blue into this little bit of process blue, and it was very close. Results by accident, I guess.

Here is what the finished work looks like. I only painted over the old letters and numbers, not the entire blue area. That way, it saves time, and costs the company less.
There are other considerations; if the area was flat, I could have just put down a bigger piece of blue vinyl, then put the white vinyl over that. The reason I didn't was because the raised metal (embossed?) areas form compound curves at the corners, laying vinyl flat there would have been difficult or impossible. The 6 was hard enough, that's why I moved the 08 toward the left. The other numbers will be aligned better. If the existing letters were vinyl, I would probably use a paint product known to adhere to vinyl, such as multi purpose screen ink.
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